The current proposal aims at establishing a confocal imaging facility in the Department of Biology of the University of Puerto Rico (UPR), Rio Piedras Campus. The equipment requested is a Confocal laser Scanning Microscope with its accessories. Confocal microscopy has become a powerful, almost essential, tool in Cellular and Molecular Biology studies. Its applications range from exquisite resolution of cellular components in fixed cells using target specific fluorescent probes and labeled antibodies to quantitative analyses of ion concentrations within a single cell. The acquisition of the equipment will impact directly the research of five investigators, their research associates, post-doctorals, graduate and undergraduate students. These researchers aim at using the equipment to answer questions related to: (1) Localization of molecules or cellular components in a single cell or organelle via fluorescence probes and the changes produced by physiological and pharmacological perturbations. (2) Imaging intracellular calcium concentration changes produced by activation of membrane channels and/or by the addition of marine invertebrate toxins by using fluorescent calcium indicators. (3) Explore the relationship between cells and between cells and the extracellular matrix during development and regeneration processes by high resolution double labeling immunohistochemistry. (4) Characterizing novel gene products. The establishment of the confocal facility will also serve to strengthen the Cellular/Molecular Program of the UPR and provide indirect benefits to many other institutions on the island who depend on facilities at the UPR for collaboration and the training of their faculty, students and other employees.